Posts Tagged ‘Human’

10:10:10:100 by 2100

The “success” of a species is generally taken to be indicated by its population though it is of course possible to have quantity without much quality of life. In general however, an increasing population of any species does indicate the sufficiency of food, the ability of the species to withstand competition from other species and the ability to breed successfully in the prevailing conditions. And so it is for humans. Based on population, modern humans have never been as successful as they currently are. And in spite of all the doom-sayers and the alarmists, the fact remains that more humans are being fed and housed and are achieving some large part of their aspirations than ever before. They are living longer than ever before and their life expectancy is still increasing – currently by about 2 -3 months every year.

However just looking at the crude birth rate (number of births per 1000 of population) might lead one to a conclusion that there was a catastrophic decline in the human species.

Crude Birth Rate / 1000 of population

Birth rates have declined from about 37/1000 in 1950 to less than 15/1000 now and are projected to be around 10/1000 by 2100. For any other species that would be a catastrophic decline. But of course that conclusion would be quite wrong when applied to humans. The mortality rate of humans has also declined drastically as medical and public health advances have been made. And human ingenuity has maintained food and material supplies such that life expectancy has increased in spite of a booming population.

Birth and mortality rates

The fact that population and life expectancy have increased simultaneously is a clear indicator that the quality of life has not deteriorated. There may be problems of equitable distribution but there is no shortage of food or other resources – and no prospect of any catastrophic shortages occurring. All other indicators tell the same story. Infant mortality, poverty and malnourishment are all at all-time lows and declining even if these can be lower still. The real GDP per capita is increasing. Leisure time (time not spent on the requirements for survival) is increasing and for more people than ever before. The age of space exploration and the potential for access to new sources of raw materials and even real estate has already begun.

There are many who rail against the consumer society and materialism but generally do so from a position of some comfort. There are others who moan the loss of spirituality and yearn for a return to a simpler life but they too are not quite ready to return to the trees. There is no shortage of doom-mongers and alarmists who merely keep pushing their doomsdays into the future where they cannot be disproved.

It is a question of attitude. There are those who would prefer to be governed by fear (the precautionary principle) and there are others who would move forward in spite of their fears.

But the reality is that the human species – with all its warts and threats and self-inflicted problems – is thriving.

Population and life expectancy WPP2012

It is not a forecast or an objective but merely the inexorable arithmetic of demographics which leads to the inevitability of 10:10:10:100 around the year 2100.

10 billion population, 10 births per 1000 of population, 10 deaths per 1000 of population and a life expectancy at birth of 100 years.

The man in question may well have been Neanderthal. Fibre artefacts rot easily and the oldest remains found of a man-made, twisted, fibre “cord” or “string” dates from only about 30,000 years ago. A new paper describes perforations in upto 90,000 year old, stone and tooth artefacts as well as shells from Abri du Maras and other Neanderthal sites in France, indicating they had once been threaded on “strings” and worn as pendants.

People should be persuaded against having large families, says the broadcaster and naturalist

Much of what he is reported to have said is perfectly sound but many of the conclusions then present a pessimistic and apocryphal – a very Guardianesque – view. In fact I suspect that the spin is entirely due to the Guardian’s reporter and the Guardian’s remarkable ability to see a looming catastrophe in every advance.

That with falling fertility rates, world population will continue to rise at a decreasing rate and stabilise by 2100 is just a matter of arithmetic. But a 100 years from now we will face the challenges of a slowly declining population. That natural selection is “defeated” when even weak individuals are cared for and are not allowed to die is not something to regret. We are in the process of artificial selection over-riding natural selection and at a quite different pace, but it is just another challenge for humans – not something to wring our hands over. In fact we are already practicing a sort of eugenics by default.

Sir David Attenborough has said that he is not optimistic about the future and that people should be persuaded against having large families.

The broadcaster and naturalist, who earlier this year described humans as “a plague on Earth”, also said he believed humans have stopped evolving physically and genetically because of birth control and abortion, but that cultural evolution is proceeding “with extraordinary swiftness”.

“We stopped natural selection as soon as we started being able to rear 90-95% of our babies that are born. We are the only species to have put a halt to natural selection, of its own free will, as it were,” he tells this week’s Radio Times.

“Stopping natural selection is not as important, or depressing, as it might sound – because our evolution is now cultural … We can inherit a knowledge of computers or television, electronics, aeroplanes and so on.”

Attenborough said he was not optimistic about the future and “things are going to get worse”.

“I don’t think we are going to become extinct. We’re very clever and extremely resourceful – and we will find ways of preserving ourselves, of that I’m sure. But whether our lives will be as rich as they are now is another question.

“We may reduce in numbers; that would actually be a help, though the chances of it happening within the next century is very small. I should think it’s impossible, in fact.” …

… he also appeared to express qualified support for the one-child policy in China.

He said: “It’s the degree to which it has been enforced which is terrible, and there’s no question it’s produced all kinds of personal tragedies. There’s no question about that. On the other hand, the Chinese themselves recognise that had they not done so there would be several million more mouths in the world today than there are now.”

He added: “If you were able to persuade people that it is irresponsible to have large families in this day and age, and if material wealth and material conditions are such that people value their materialistic life and don’t suffer as a consequence, then that’s all to the good. But I’m not particularly optimistic about the future. I think we’re lucky to be living when we are, because things are going to get worse.”

“Worse” is a matter of judgement.

We will feed and house more people than ever before. We will take care of more of the elderly than ever before. We will each have more and affordable energy available to us than ever before. We will educate and empower more people than ever before. More of us will see more of this world than ever before. We will face more challenges than ever before. That’s not “worse”.

ANN ARBOR, MI—In a breakthrough study that researchers say adds important insight into the evolution of Homo sapiens, scientists at the University of Michigan confirmed Thursday that human beings are slowly evolving into mollusks. “Evidence shows that modern humans emerged on the evolutionary timeline about 200,000 years ago, developed into the highly evolved hominids of today, and are now transforming into soft-bodied invertebrates,” said the study’s lead author Dr. Mitch Keneally, adding humans have already started turning into snails, slugs, and octopi, evidenced by their increasingly amorphous figures. “Over the next 1,000 years, we’re going to see people developing gills, a hard protective shell around their torsos, and a large, muscular foot in their dorsal region that will help with locomotion and mucus secretion. The world is changing rapidly, and those who can’t filter seawater aren’t going to be able to survive.” Scientists added that the evolutionary trajectory isn’t all that surprising considering that mollusks themselves descended from monkeys just 5,000 years ago.

Of course this begs the question as to how humans are likely to evolve over the coming generations?

Humans and chimpanzees ancestors split some 7-8 million years ago and it took some 350,000 generations after that divergence for evolution by natural selection to produce anatomically modern humans (AMH). (This of course raises the question as to how chimpanzee evolution proceeded to reach modern chimpanzees while humans were developing into homo sapiens?).

It has been only about 10,000 generations since AMH appeared and only some 6,000 generations or so since modern humans left Africa. A very short time in evolutionary terms yet in this period humans have evolved to exhibit the various races of man that exist today. This differentiation is primarily superficial and all humans existing are capable of mating and producing viable offspring with each other. In theory humans existing today would also be compatible and – in the main – capable of mating with the humans of 6,000 generations ago. In practice a meeting of modern humans with those from 120,000 years ago would be an exaggerated replica of modern man meeting with isolated tribes in the 20th century. These isolated branches of humanity generally had lower levels of immunity to the bacteria carried by their distant cousins and were ravaged by disease after such encounters. The bacteria we carry are probably greatly different to those that humans carried at the dawn of anatomically modern humans. Probably no such meeting or mating would be very successful and one or both would probably succumb to disease brought on by the other’s bacteria. Nevertheless the genomes of the two – even after 6,000 generations – would not be so very different and probably still be compatible. In any primate species a generational distance of over 20,000 between individuals will probably disqualify any theoretical possibility of successful mating.

There has been a gap of 50-65,000 years between the genetic time-line of the Out-of-Africa theory and archaeological indications of the earlier presence of anatomically modern humans outside of Africa. But the genetic evidence is now going back in time and approaching the archaeological time-line. “Out-of-Africa” is beginning to look much more like “Out-of-Africarabia”.

The origin of language was once a forbidden subject and in 1866, the Linguistic Society of Paris went so far as to ban debates on the subject – because it was considered too speculative to be a matter for serious people! But I find the question fascinating. When and how language developed remains a mystery. But with communication and language being such a clear measure of the distinction between humans and other primates, it seems obvious that there must be some genetic basis for this difference.

Ten years ago this month, a team of University of Oxford scientists published a description of a family who struggled with words. By comparing their DNA, the scientists zeroed in for the first time on a gene associated with language, dubbed FOXP2.

Genetic evidence suggests that the basis of language appeared among hominids prior to the evolutionary split that gave rise to Homo neanderthalensis. Having the genetic wherewithal for having language does not of course prove that hominids had language 400,000 years ago. But I would suggest that the need for a particular characteristic (whether for survival or merely for coping better with the prevailing environment) itself predisposes for those factors which enable the correct expression of the relevant genes to enhance the characteristic. And this leads to the role that epigenetics and the inheritance of factors controlling gene expression – rather than mutations of the genome – may have had in the development of language.

Pungent body odor from sweaty adult human skin is unique in the animal kingdom. Humans turn out to be particularly smelly because odors are released from nearly every part of the body while other species living on us are simultaneously emitting odors too.

Lead author Renate Smallegange explained to Discovery News that “the microorganisms on our skin use the materials present on our skin and in our sweat for their own metabolism. The microorganisms convert non-volatile compounds into volatile compounds.”

Smallegange, a Wageningen University entomologist, and colleagues Niels Verhulst and Willem Takken, analyzed data on the chemical structure of human sweat. They conclude that “sweat-associated human volatiles are probably the primary determinant factor in the host preference of anthropophilic mosquitoes.” These insects can carry life-threatening diseases, such as dengue, yellow fever and malaria.

So far, the “recipe” for synthetic human sweat appears to contain a complex blend of carbon dioxide, ammonia, lactic acid, and seven other carboxylic acids. The latter “have a sweaty smell,” Smallegange said. Mosquitoes are very attracted to this odorous concoction when scientists whip it up in the lab. ……

Adult humans instead frequently emit water, proteins, amino acids, urea, ammonia, lactic acids and certain salts — much of which can stink. During puberty, the glands that release these components mature and are colonized by bacteria.

“So even though parents can recognize their preadolescent children by olfaction, children have a less ‘pungent’ body odor compared with adults,” the researchers explained, adding that children also produce sweat at a lower rate than adults do.

The mosquitoes studied by the scientists bite sweeter smelling infants and children less frequently. Having a strong body odor can be useful at times, however. Smallegange mentioned that the odors that emerge during and after puberty are likely tied to “sexual maturity and mate choice.” Prior research determined that we can even distinguish ourselves based on hand smell alone.

The scientists further report that men sweat more than women do during exercise. Nevertheless, the concentrations of smelly, volatile carboxylic acids are basically the same for men and women.